Drill



- June 17, 1930.

Filed March 14 1927 C. A. SIGNELL ET L Patented June 17, 1930 UNITED STATES FATE CARL A. SIGNELL AND OTTO SIG-NEIL, F JAMESTOWN, NEW YORK .DBILL Application filed March 14, i927. Serial in. 175,244.

This invention relates to improvements in drills for work in stone although they may be employed for other purposes. One obj ect is to provide a drill that is of simple construction, very durable and that attains the maximum efficiency in use.

With the foregoing and other objects in view the invention consists in the combination and arrangement of parts to be hereinafter fully described, pointed out in the appended claim and illustrated in the accompanying drawin which forms a part of this ap lication and III which-- 1g. 1 is an enlarged fragmentary sectional view of the drill shown in Fig. 2.

Fig. 2 is a perspective view of the drill.

Like reference characters denote corresponding parts in both views.

Drills of this nature which are designed for heavy work must necessarily be made of the best and in the ordinary one-piece drill it is necessary to discard the complete. tool it any part thereof is worn excessively or broken. The present tool is designed with a separable head which, when worn, may be discarded for a new one which may be fitted to the same shank thus greatly prolonging the life of the shank portion of the tool thus greatly reducmg the cost of tools employed in this work.

The reference numera 1 denotes the shank of the tool having the threaded, non-fluted end 2 adapted to receive the interiorly threaded hollow head 3. A centrally disposed bore 4 extends longitudinally of'the shank from end to end.

recesses 5 the depth of which increases as the recesses recede from the upper or interiorly threaded end of the tool and the ridges 6 between the recesses are'bevelled slightly from their lower to their upper ends.

The head is formed interiorly sageway 7 that the shank and with branch that extend to the cutting Transverse cuttin formed upon the ee or workin end of the head, one only of said cuttinge ges, 10, ex-

with a paspassageways 8 9 end of the head.

tending diametrically across the end of said and 'at right angles to each work.

feature 0 tool steel which is very expensive and intercommunicating water The head 3 is formed with a plurality of as our own we have hereto registers with the bore- 4 in edges 10, 11,12, 18, 14 are head and being spaced by parallel grooves 15, 16 from the remainingcutting'edges. The cutting edges 13, 14 are se arated by radial grooves 17, 18 and divide by said grooves the grooves '15, 16 into a plurality of groups, each group comprising cutting edges 11, 14; or 12, 14; or 11, 13; or 12, 13, and the cutting edges of each group being disposed other. In use the tool is supplied with water which passes through the bore 4 of the shank and thenthrough the pasageways 7, 8,9 upon the The chips, dust, etc. resultin from the operation of the tool will the recesses 5 and will not b ock or obstruct the water assages. This is a very important f the head as the stoppage of these passages impairs the efiiciency of the tool.

What is claimed is In a drill, a shank havin a longitudinal central bore, a head adapte for removable attachment to one end of said shank, said head having a recessed periphery, the depth of said recesses being greater at one end than at the other, the ribs between said recesses being bevelled from the outer to the inner end of said'head, cutting edges formed upon cutting edges, the

in said head communicating with the bore in said shank.

In testimony that we claim the foregomg aflixed our sig- CARL A. SIGNELL. OTTO SIGNELL.

natures.

by parallel grooves 80 

